Fuel injector pump



Sept. 2l, 1954 J. R. EMERSON FUEL INJEcToR PUMP 5 Sheets-Sheet l Filed Feb. l1. 1949 www @i www SePt- 21, 1954 J. R. EMERSON 2,689,527

FUEL INJECTOR PUMP Filed Feb. 11. 1949 5 Sheets-Sheet 2 SePt- 2l, 1954 .1. R. EMERSON 2,689,527

FUEL INJECTOR PUMP Filed Feb. 11. 1949 5 Sheets-Sheet 5 jj f3.3 j 135 III Hl U 33 #+2 J2 53 Jig 27 *v 3j 29 J7 T-7 @we 353'? l 5J 319 J5 J. R. EMERSON 2,689,527

FUEL INJECTOR PUMP Sept. 2l, 1954 Filed Feb. l1, 1949 5 Sheets-Sheet 4 H Q J2 f IIH l 126 124' 127 125 f6 ,M

j] llzu 17 jj 129 125 J3 Q l 131 /fg l .3.9 53 j@ 153 26 jg@ y 151 12,5 faz/enfer.

` fo/n, H. E 5072/ ../.49

152 B M7 146 j@ 5 Sheets-*Sheet 5 J. R. EMERSON FUEL INJECTOR PUMP Sept. 2l, 1954 Filed Feb. 11. 1949 Patented Sept. 21, 1954 FUEL INJECTOR PUMP .John R. Emerson, Flint, Mich., assignor to Borg- Warner Corporation, Chicago, .111., a `corporation .of Illinois Application Febr-nary 11, 11949,'Seria1 No. 75,757

1'1 Claims.

l i l This invention relates to `faduel injector pump, Aand more particularly to a fuel injector vpump Yof the single plunger variable `stroke type, the length of the plunger injection stroke being controlled in accordance with engine :manifold pressure, and distribution from the single plunger chamber to the various `engine cylinders .being controlled by a distributing disc.

Theoretically, the variable stroke injector plunger should provide the optimum control of fuel metering since in this type of pump when more fuel is required, the stroke is increased, whereas when less `fuel is required, the stroke is merely reduced. Actually, it has been found very diflicult in practice to construct a variable `stroke injector type pump which would provide both eflicient and satisfactory .operation and at the same time the required Vflexibility of operation. Particular `diilicu-lty has been encountered in providing a variablestroke mechanical drive for the injection plunger. Further, while it is known to use manifold pressure or density as an indicator for metering, the control mechanism heretofore used has been `bulky and excessively complicated.

An object of the present invention is to provide a new and improved fuel injector pump.

A further object of the present invention is to provide a fuel injector pump of the variable stroke type incorporating ,a simple and efficient .mechanism for Varying the length of the plunger stroke.

A further object of .this invention is to provide in a fuel injector pump an improved pressure :responsive control mechanism 'for operating the plunger stroke varying means.

` In accordance with one embodiment `of this invention, hydraulically operated means .are .employed to drive the `plunger and .to .control the length of the plunger stroke. The pressure responsive control mechanism aided by a servo system changes the position `of a stop Vplunger and the maximum stroke of the injector plunger as well as the volumetriczcapacity of the injector displacement chamber is determined bythe position of this stop plunger. A supply pump of the Istraight spur gear type is incorporated in the injector pump, and-not -only supplies fuel -for the `displacement chamber of the plunger portion of *the pump, but also supplies fuel under pressure to operate the fuel injector plunger and the servo `piston in the variable stroke regulating .'control.

Other objects and .advantages :of fthe present fiinvention will be .apparent .from `the `following f 2 detailed description :taken Ein conjunction with the drawings wherein:

:F.ig. lis a yschematic diagram showing primarily Vthe iiuid pressure connections .of the various parts of the injector .pump or this invention;

Fig. 42 is a vertical, sectional view of the pump taken along the line 12`2 `of Fig. 3;

Fig. 3 is .a vertical sectional view taken along the =line 3-3 of Fig.'2;

Fig. 4 is a detailed sectional view taken along 'the line `4-4 `of Fig. '3;

Fig. `5 is `a detailed sectional view Vtaken along the lineS-Ti of Fig. 2;

Fig. `6 :is a 'sectional view taken along the line -E--G of Fig.:2;

Fig. 7 is a sectional -view taken along `thealine '1-1 of Fig. 2:;

Fig. -8 -is `a `sectional view taken 'along the line `8-8 of'liig. 2 and Fig. A9 isa transverse sectional view taken along the Yline9-ilof Eliig. 8.

The fuel injector I:pump herein described and shown in the drawings is designed for use with .a six cylinder engine in `which the `drive from the `eng-ine is one and one-half ytimes engine speed and the 4distributing Adisc runs at Yone-half engine speedpor :cam shaft speed, on a four cycle engine. However, the -fuel injector `pump of this invention could 'be used for example on a four cylinder vengine if the drive Afrom the engine were at engine speed and the gearing between the driven gear and the Idriving `gear in the fuel supply ipurnp Were such that the .distributing disc ramone-half eng-ine speed. This is primarily Va Y 4matter of gearing .and requires .but minor modication, the nature of which will be obvious At0 Jone skilled sin the art trom-the following detailed .description of this invention. Thus, while this invention is `shown in the form employed for a six cylinder engine, it will be understood that Vby simple rnodication the .arrangement of this invention can be adapted to an engine having either `more or less than six cylinders.

The fuel injector `pump of this invention -coni- I'prises the following principal elements: a gear Vpump .t0 driven by the engine `for pumping fuel `from-the supply tank `to the injector pump and for supplying the hydraulic pressure required in -accordance with this invention. A `variable stroke, hydraulically actuated injector Vplunger' '37 supplies fuel under high pressure to Aa fdis- .tributing mechanism, indicated at 5B, which is connected `tousupply fuel under pressure to the cylinders of the engine l(not shown) in rotation. "Theestroke of .the 'injector plungerl is controlled by a stop plunger 15, the position of which is regulated in accordance with manifold pressure by a pressure sensitive device |02 and associated servo means |63. Compensation for variation in atmospheric pressure is provided by a capsule |38 associated with the manifold pressure responsive device |02.

In Fig. 1, these elements are illustrated in simplified manner so as to make clear their related functions. Reference should be made to Fig. 1 as the following description is read to facilitate an understanding of the interrelation of the several components of the fuel injector pump of this invention.

Referring now to Fig. 2, it will be seen that the gear pump IIJ is enclosed within the right portion of a fuel injector pump housing |I and includes a large driven gear I 2, supported on shaft I3 which is journaled in and rotatably supported by an elongated sleeve bearing I5 mounted in the left portion of the housing II, as shown in Fig. 9. The driven gear I2 is of the straight, spur gear type generally employed in gear pumps and meshes at its lower side, as viewed in Figs. 2 and 6?, with a similarly formed, driving gear I6 of substantially smaller diameter. Driving gear I6 is sup-ported on and keyed to driving shaft I1, the shaft I1 extending to the right, as viewed in Fig. 2, and terminating outside the housing in a spline I8 which is adapted to engage a suitable driving spline in the engine. Shaft I1 is journaled in a bushing 20, located on the right side of the gear I6, as viewed in Fig. 2, and packing 2| is provided` adjacent the right end of the bushing 20 to prevent leakage of fuel from the pump into the engine, the packing 2| being retained by packing ring 22 and a helically coiled compression spring 23. When the pump is assembled on the engine, it is supported in position thereon by suitable bolts (not shown) carried by mounting flange 24 of the housing II, the right end of the spring 23 then bearing against the engine housing.

The embodiment herein described of this invention is, as aforesaid, intended for use with a six cylinder, four cycle engine and the spline I8 on the shaft I1 is therefore arranged to engage a companion spline on the engine which rotates at one and one-half times engine speed. Driving gear i6 is selected with reference to driven gear |2 so that the shaft I3, which also drives the fuel distributing mechanism as will be more fully explained hereinafter, rotates at one-half engine speed, that is to say, the driving gear has a diameter one-third the diameter of the driven gear I2.

' is located Vabove and to the right of the gear pump I0, as viewed in Fig. 2, being enclosed in a suitably formed portion of the housing I I, and is connected to the discharge side of the pump I9 so that pump pressure is applied to a plunger 28 of the by-pass regulating valve 21, the pressure tending to move the plunger 2B against a regulating spring 29. Discharge port 3| of the regulating valve is connected to the inlet chamber 32 of the gear pump I9 so that by-passed fuel is recirculated through the system in conventional manner. The plunger 28 has a number of axially extending grooves 33 formed in its periphery and as the pressure against the plunger 28 from the pump I0 exceeds the counterpressure from the regulating spring 29, the plunger 28 moves to the left, as viewed in Fig. 5, thereby increasing the by-pass ilow and tending to main-` tain a constant pressure for the output of pump I0. The by-pass operation of valve 21 is easily seen from Fig. l.

Fluid pressure from the pump Ill, regulated by the by-pass valve 21, is supplied from the outlet port V26 through a downwardly extending duct or channel 34, which connects at its lower end, as shown in Fig. 2, to an upwardly extending channel 35 and from the channel 35 to the underside of a piston 36. `Piston 36 carries on its upper side a vertically disposed injector plunger 31, the lower end of which is rigidly secured to the piston 36. In order to provide for intermittent actuation o-f the plunger 31 in timed relation to the operation of the engine'with which the pump is to be associated, a valving sleeve 38 is provided, the right portion thereof, as viewed in Fig. 2, being solid and secured to the left side of driving gear I6. lThe valving sleeve may be integrally formed with the shaft I'I to which the gear I6 is keyed and in any event is designed to rotate with the gear I6 and thus with the engine with which the pump is associated. Valving sleeve 38 is journalled in a long bushing 39 which is mounted in the housing I and the solid portion of the sleeve 38 has a transverse aperture or passage 9 formed therein, the ends of which register twice in each complete rotation of the sleeve 38 with the upper end of channel 35. Bushing 39 is suitably apertured at 33a and when aperture 4I) is in register with the channel 35, it will be evident from Figs. 2 and 3, that a con-r tinuous passage is provided whereby fluid pressure from the pump I9 may be directed through a bushing 4| to the underside of piston 36. It will be noted that the upper end of bushing 4| is provided with oppositely disposed, transverse apertures 42 as well as the central aperture Ma,-

opening at its upper end against the underside of the piston 36, whereby fluid pressure may be exerted uniformly over the underside of the piston. The cross-apertured upper end of bushing 4| is enlarged to form a shoulder 44 which seats on the lower edge of piston chamber 46, while the lower end of the bushing 4| is slightly spaced from bushing 39.

In one embodiment of this invention, the plunger 31 was made to have an area one-tenth that of the piston 36 and the pressure delivered by the plunger 31 was therefore ten times that applied to piston 36. Thus, where the regulated pressure of the fuel supply pump I0 is set at fty pounds per square inch, the injection pressure to the engine cylinders will be five hundred pounds per square inch. Because of the high pressures present at the plunger 31, it is desirable to fit the plunger 31 very closely into cylindrical supporting block 43, which as may be seen in Figs. 2 and 3 is threaded into the midportion of the chamber 46 and has its lower end located substantially above the upper end of bushing 4|. However, the piston 36 may be fitted somewhat more loosely in the lower portion of chamber 46 of the housing II, since the piston 36 has no `:shown in Fig. 3, one lend of which `communicates "with the upper portion of the 4chamber :et virrimediately beneath .the plunger ,block 4:3 :and the other end of `which .is rconneeted :to a fur-.ther return channel 41, which :leads 4to a channel ."48 `extending parallel A.to waiving .sleeve 3B. `Aipair ".df oppositely `:viisposed apertures `4i! .are formed tin Athe hollow, left portion of the valv'ing .sleeve .318, being spaced somewhat to :thelleft `ef the rcross aperture 4.0 formed in Athe :solid .portion of the .'sleeve, .as -viewed iin VF.ig. :2, mid fangu'larl-y d-is -fpilaced 190 therefrom. 'The :apertures 49 .are.;ar-

ranged to V:register through can aperture 49a in 'the `bushing 3.9, with La :short channel l48a coninecting at `right `angles to channel 48, `as shown inFig. 8. Apertures r4.5 communicatethroughfthe hollorw interior of the left portion "oi the valving `:sleeve 38 `with a .slot y:5t formed inan extended,

`lower portion 5I of a dish-:shaped cover iplate 512. The cover plate 52 forms a `partof th'e housing for the fuel distributor mechanismlSB and is ssuit- :ably bolted `to the pump housing at the .left :side thereof, as viewed in 2. .The :slot 5:6 .extends n.upwardly and to the right, `as viewed `in Fig. f8, connecting at its upper end to` a ,channel 53 which extends to the right, as viewed in Fig. to 'the .inlet chamber T32 rof the .gear pump Irl).

Fuel is returned from under the piston 36 to the inlet chamber .32 :during downward `movement :of lthe piston 36 'through a drain channel `154, the right end of which,as viewed vin Eig. 2, is cenn nected to port 54a Vformed vin 4:the left side o'f the bushing 4I adjacent :itsLlower end. 4Channel 54 has connected thereto :a `downwardly :extending `ehannel `55, the lower end 'of which 'is arranged to .register through an `aperture-:55a in the `.valvsleeve bushing `39 with the .cross :apertures f4.9 formed in the valving sleeve .'38` twice during .a single revolution `of the shaft The :discharge .end lof channel 55 is displaced 490 with reference to the discharge end of rtransverse channel 46a :associated with nreturn channels 45 and "41 and thus registration with apertures 49 occurs :only when the apertures 49 are vertically aligned .and the pressure path to the underside of piston 136 is closed. In `Fig. :2 the apertures 4;'.9 are hori-l zontally aligned, that is one of the apertures is registered Vwith Ychannel 48a `permitting .discharge ,from the upper side of the piston 36.

.In accordance with 'thisinvention, the injector :plunger 31 is positively actuated in `both directions, fuel under pressure `-being supplied to 'the AYunder `side of the piston .36 Vwhen lit is desired 'to inject fuel, and 4fuel under pressure being supplied to the `upper side of piston '36 `when it is `'desired to return the piston. Referring to Fig. .3, the pressure `path to the upper Yside .of .driving piston 36 will be seen to include a `transversely extending channel 55, the right end of which con- ;nects to the output port 125 ofthe gear pump IIJ and the left end of which is :arranged 'to register `through :an aperture .56a Aformed in bushing .3,9 `with :the cross aperture 40 .in the valving sleeve M -when this latter apertureis in horizontal-alignment, Vas viewed `in Fig. L3. When .so aligned,

the `tend-:cf the :aperture 40 :on the `.opposite :side

from the channel 56 registers with fone 4end :of 4a 'channel 551., bushing .39 being suitably apertured :at 1a. The other end .of channel 51 .is .connected to Ychannel 41, and then 'through channel `4.5 to the upper side of the piston 3.6. When aperture f4.0 is aligned with channels 56 and `51, pressure is supplied through the channels and '45 to the upper side of rpiston 36 forcing the piston downward. At this same instant, one :of "the apertures 49 in lthe val-ving sleeve .-38 is Aaligned with channel 55 in the return path from the lower side of Vthe piston 36, thus permitting fuel 'to be readily .expelled from .under .the piston 36 `as `.the piston moves downwardly. Thereafter,

when theualving shaft 38 .has been .rotated 90, pressure is .applied tothe underside of .the piston 36 to force :the piston upward .through .a pressure path including ,the bushing 4I, aperture .'40, channel 35, and vchannel 34 connected to pump .discharge :port 26. VWith this 90 .rotation,xone of cross apertures 49 is now aligned with the return `channel I48a and 'fluid is permitted to .drain from the upperside of thepiston 3'6 as :this Apiston is moved upwardly. Thus itwill vbe seen that "no impediment :is presented `.to .the movement `o1 .the piston A36 in either direction .in which it is being driven.

Since the apertures 4B and 49 in the valving sleeve 36 will each register twice per revolution with their associated channels, the number of `cycles. of the piston 3'6 will be twice the number of revolutions of the driving shaft I1, and since this shaft is revolving at one and one-half .times engine speed, the .injection plunger 31 `will make three complete cycles per engine revolution, thus giving three injection .strokes per :engine revolution, as required ina six cylinder engine.

.Fuel from the fuel supply pump I reaches displacement 'chamber 58 above the injector .plunger .31 through an upwardly extending .channel 5.0, shown in Fig. 3, `which is connected to the outlet port 26 of the gear pump I0 at its .lower end, and has its upper end connected to a horizontally extending channel 6I, best illustrated 'in Figs. L13

Aand 9. The lower end of channel 6I, as viewed in Fig. 9, is arranged to `register successively with arcuate `slots .62 formed Ain a `dish-shaped distributing disc 63, which rotates with the driven .gear shaft I3. ,The .disc 63 is enclosed by `the cover plate 152 'and .is .axially vspaced therefrom to provide a chamber l(ill lying on the Vopposite side of `the disc v[53 from thatto 4which the chan- 'nel n6I extends. AThe chamber 64 extends around the periphery .of the disc 6.3, as .clearly ,shown in Fig. 9, and the annular chamber 65 `defined by the periphery of the disc 64 and the inner surface of theplate 52 communicates through a chaninel A6b with the displacement chamber 58.

The .distributing disc 63 is rotated with the driven gear I'2 by .the .shaft I3 which extends from the lower side of the gear I2, as 'seen in Fig. 9, a .spline 68` being .provided `at the lower end of theshaft I3 and .keyed to the dished portion of the vdisc 63. The distributing disc 263 lits lclosely against the `end face of the lhousing Ill `and is held rmly against .this face lby a thrust `ball 1!) vand `associated :compression spring 1I. "The fuel vpressure in the -chamber 64 acting against the large surface on the lower side :of the disc 53, in .conjunction with the pressure of spring 11, maintains `a .sufficient pressure :of .engagement of Athe :disc 63 and the .housing II Ato ,provide the required seal.

As the yinjection plunger 31 .movespdownwardlm vspaced radially outwardly of the slots 62.

7 one of the slots 62 registers with fuel supply channel 6I and fuel passes into chamber 64 and through channel 66 into the displacement chamber 58, as described. Thus, there is a combined action of supplying of fuel under pressure and a suction action on the part of the downwardly moving plunger 31 providing rapid lling of the injection chamber. The slots 62 are arranged to be out of registry with channel 6l when injection plunger 31 is moved upwardly so that fuel under injection pressure cannot be forced back into the supply system.

As the injection plunger 31 is moved upwardly .by actuation of the piston 36, fuel is forced from the displacement chamber 58 back through the channel 66 to the chamber 64 on the' lower side of the distributor disc 63. The pressure of the fuel forced back through the channel 63 is, of course, as many times greater than the initial supply pressure as is the area of the piston 36 greater than the area of the injection plunger 31. An arcuately slotted port 12 is formed in the distributing disc `63, and as shown in Fig. 8, is This port 12 is arranged to register successively with the inner end of each of six outlet ports 13 formed in the housing Il and suitably connected to the various cylinders of the engine. It will be understood that the location of the outlet ports 13 is such that when the distributor disc port 12 is registered with one of the ports 13, the supply channel 6l is not registered with any of the slots 62 and thus full injector pressure is delivered only to the selected one of the ports 13.

In actual practice it has been found desirable to select the engine injector nozzle valves (not shown) so that these valves will not open at the fifty pounds pressure normally present at port 12. Thus, the discharge port 12 can be in full registry with port 13 before the injector plunger 31 lstarts its upward stroke. By having ports 12 and 13 in full open registry, as shown in Fig. 8, at the time the high injection pressure occurs, wire 'drawing of the fuel and erosion of the ports is avoided. Furthermore, this arrangement makes unnecessary accurate timing of the start of registry of these ports in order to obtain accurate timing of the fuel injection into the engine cylinders. In other words, the timing is dependent only on the start of the upward motion of plunger 31, that is, of the injection stroke.

It will be apparent from the foregoing that in accordance with this invention, there is provided a simple but eflicient fuel injector pump wherein the injector plunger is hydraulically reciprocated by pressure supplied from the same pump which is employed to draw fuel from the supply tank. The structure thus far described employs a minimum of moving parts and where no variation in the length of the injector plunger stroke is required, this structure has been found to be very satisfactory. The structure described, however, is particularly well suited, because of the hydraulic drive, to regulation of the length of the injector stroke in accordance with one or more selected operating conditions or characteristics of the engine with'which it is to be associated.

In accordance with this invention, the length of the stroke of the injector plunger 31 is varied from a minimum for idling the engine to a maximum for full throttle or full load engine operation, the length of the stroke of injector plunger 31 determining the quantity of fuel injected into each cylinder of the engine. In this embodiment `of vthe invention, the plunger stroke length is regulated in accordance with engine manifold pressure, as this engine characteristic has been found to be a useful and reliable variable. However, it will be understood that other characteristics may well be substituted therefor or integrated therewith.

Referring to Figs. 2 and 3, it will be seen that the lower end of an adjustable stop plunger 15 extends into the displacement chamber 58 at the upper side of the injector plunger 31. The amount which this stop plunger 15 extends into the displacement chamber 58 determines not only the length of the injection stroke of plunger 31 but also determines the volumetric capacity of the displacement chamber thus regulating the amount of fuel which is drawn into the chamber on the downward stroke of the plunger 31. The plunger 15 is slidably journalled in a heavy cylindrical bushing block 16 which is, in turn, threaded in an enlarged upper portion 11 of the cylindrical chamber 46 of the housing Il in the lower portion of which the piston 36 is journalled. The lower end of the block 16 is slightly spaced from the upper end of injector plunger block 43, this space providing the displacement chamber 58. A shoulder or ange 18 is formed about the midportion of the periphery of the bushing block 16 and seats on a suitable recessed ledge 19 at the upper edge of the chamber portion 11. Packing 8i is provided in the bushing block 16 and is disposed about the stop plunger 15 to prevent leakage therebetween, and the packing 8| is retained in position under compression by a gland nut. y82 peripherally threaded into the lower end of the bushing block 16.

The position of stop plunger 15 with respect to displacement chamber 58 and injector plunger 31 is controlled by a cam 83, which is supported on a transversely extending stub shaft B4, the ends of which are suitably journalled in the two opposed walls of a U-shaped cam positioning block 86. Tne block 85 is slidably mounted in a suitably formed upper portion 81 of the housing Il, as shown in Fig. 2. Two adjustments are provided for the positioning of the stop plunger by cam 83. One adjustment comprises raising or lowering the cam by moving the block 86; the other comprises pivoting the cam on the shaft 84 by means of forked lever arm 85.

The cam positioning block 86 is vertically adjustable in housing portion 81 of the pump housing l I by an adjusting screw 86 by which the block is supported in housing portion 81. The adjusting screw 88 is threaded in a suitably threaded aperture 98 formed in the upper end, that is, in the cross portion of the positioning block S6 and is provided with a shoulder or flange 9i, the upper surface of which bears against the underside of the housing 31, the shank of the screw 88 extending upwardly through an aperture 92 formed in the housing 61. A knurled head 93 is provided on the upper end of the screw 88 to facilitate turning the same and a coiled spring 94 is positioned between the head 93 and the upper side of the housing 81 to hold the iiange 9| against the underside of the housing 81. As may be seen in Fig. 2, a guide screw 95 is threaded into the left side of the housing 81 and extends into a longitudinal groove 96 formed in the pe-` riphery of the cam positioning block 86. Guide screw 95 prevents rotation of the cam positioning block as the adjusting screw 88 is rotated. A second screw 91 cooperates with the screw 95 to holdin position a flat spring 98, the upper end of which bears against the knurled surface of the screw head 93 and prevents accidental; rotationthe; position of theA cam 83., and` thus regulating,

theposition of injection plunger 3'lto. obtain the. best. position for idling the engine. In practice, theiidling position isset approximately correct, at the factory and the amount of adjustment permissible is therefore preferably limited by a limit pin 99 which is mounted in and which ex tends transversely from one side of the knurled` head-03. The pin 90 engages one side or the other of ratchet spring 90;. to prevent. the idle adjustment from being thrown too far out ofline by an unskilled operator.

WhileA the idlingposition of thetstopplunger lamay be` manually regulated by adjusting the positiony off the cam positioning block in the housing portion 8:1, the position ofthe stop plung.

er 1551s inaccordance. with this invention, also,`

automatically regulated iindependentlyof the adjusting block 6;` by pivoting the! cam 8,3 on the 511311234.. in response to variations in an selected eng-ine characteristic or operating; condition., Referring to `Eig. 3;, it will be seen that therev is vpricw-ided in the upper portion ofthe housing Il a vlongitudinally` reciprocable, hollow, piston shaft which has ain. annular groove [0| formed aboutthe midportion thereof to receive and engagethe upwardly extending bifurcated lever arm iof. the cam 8,3., When shaft` |00 movesV to therlght, arm 8.5: is pivoted in a clockwise direction and cam 03 is pivoted downward. Cone versely, when shaft |00 moves to the left, arm 85 isv pivoted in a counterelockwise direction and cam 83 is` pivoted` upward. When cam 83; is

pivoted downward, stop plungerl, the upper end of which is engaged by cam 8.3 is,- moved dewn into the chamber 58; toA reduce the lengthof the injector plunger stroke, whereaswhen the cam 03,-2is, pivoted` upward', the stop plunger '|51 is-'permitted to rise with respect tothe injector plunger.- It will be understood that in the operationof this fuel injector1 pump,-` there is; always a minimum pressure inthedisplacement chamber 5o,fthe order of lpounds per square inch, using thefigures, earlier.A supposed. It has been found in practice that this minimum pressure exerted against the underside .of stop plunger `isade quateto cause` the plunger to follow the cam |33` at. all times. -f

Movementof the, piston-.shaft um to. thought or to the left, as viewed in Fig. 3',.i s controlled byl a pressure responsive mechanism, indicatedgen` erallyY at |02, which. may" be connected to. the manifold of the engine. Thismechanism will be described in detailhereinafter. ABecause of the relatively high pressures involved in the operation of the fuel injector pump of this invention, `it is notfeasible to employ the manifold pressure responsive mechanism directly to control the shaft |00 and therefore a servo system |03` is associated' with the pressure responsive mechanism to providethe necessary operating power.

The. servo system |03, includes a servo` piston |0i4secured`- to the right end of shaft |00, pressure formovlngA the piston |04` being supplied from the fuel pressure supply pump` |.0` through the dis charge outlet 2li4 to au upwardly extending channel |05, connected at its upper endto channel |06, which is in. turn connectedto channel |01. The upper end of Channel., |01 registers with an axially elongated annular chamber |98 formed in the periphery of the servo piston |0,4.a,nd .bounded onits outer side bythe inner wall of! a cylindrical?.

servo piston chamber` '0 .formed in the housing' in which the. piston |.01le` isi slidably journalled'. Annular chamber |00? is.. connected through a` radially extending' passage.` |053` formed in the; body of the piston. iM to. an axially extending groove |f|| formed in the periphery of a stem.

H2 associated with.` the pressure responsive. mechanism |f02f.. The. stem ILISZ is. journaled in the hollow piston. shaft. |5210; and is longitudinally movable with respect to. the shaft lilo'. The leftV end of groove |1| Iacommunicates with an aperture H3 formed in the. shaft |00. on the` left side, of

the. piston |05., the. aperture.` |113 in turnconnect ing to piston chamber |:|4. Pressure in the. chamber IM. tends to move the piston to the right.

Pressure is supplied tothe right side of piston4 |04 through an aperture t|5:.formed in the shaft, i |00 on the opposite side thereof from aperture.

end with a short. axiallyf extending. passage. |158;` i

also formed inthe piston. |04, which connects` to piston chamber I!!A on the rightl side of piston'` |04. Chamber H9 is. defined bythe piston IM`A on the left side andzby an end plate. |2I of the housing on its right side. Guide pin |22 ixed" in the piston Ill-extends. at. its inner end into the slot I6, thus preventing any relative angular motion between. the. servo piston |041 and the stem 2 ofthe pressure. responsive assembly |02.

Fuel from thechamber Il |39` returns to the inlet port 25 of the gear. pump. through channel |23.,A

shown in Fig. Il,V which connects with channel |24, which in turn extends. to` an; annular cham. ber |25' formed inthe periphery ofstroke control:

plunger bushing.v block T6; "From.. the annular,` chamber |25V thereturn' path comprises a inertically extending` channel'T |26, shownr in'. Fig. 13. pressure regulating-i valve1..|21 `coinprisingthef.4 plunger |28 and springwl2i9, and vertically 'dise' posed passages. |.30i and' |3|Vextending tothef inletchamber of the gear: pump;

A denite differential pressure between chaine ber ||4 and chamber H0; on. theileftland right sides respectively ofi' servo. piston Hill isarailable by virtue of the fact that the pressure from the fuel supply pump is regulated bythe by-.pass pres.

sure regulating valve 21:' at, for example, the previously described 50 pounds per square. inch, while a substantially less pressure, for example 5 pounds per squareinch, is maintained by the pressure regulating valve |2"|`. in the return: path to the inlet port of the. gear pump. Assuming the fig-Y ures stated, a 4 5 pound pressure differential is available. to move therpiston |04 tothe right andV to urge the stopplunger l5: downward. be understood that theseI pressure figures given may be varied substantially Stem ||2 ofthe pressure responsive, assembly |02 is fitted. very closely Within the piston shaft |00., since the relative linear position of the stem |I'2 with respect 'Q0 the. Shaft Illll. and particularly of the grooves and ||6 with respect to the apertures |09 all@ ||5 respectively, controls the operation olf the servo. mechanism. It will be evident from the drawing that when the stem,

lt will..

' 11 I I2 moves to the right with respect to the piston shaft |00, the left end of groove H6 moves away from aperture H5, thus tending to close the passage and reducing flow of fluid therethrough to the chamber H9 on the right side of the piston |04. At the same time, the right end of groove HI registers more 'fully with aperture |09, thereby increasing the ow to the chamber H4. This combined action increases the pressure differential between the chambers H4 and H9 and causes the piston |04 to move to the right in the usual follow action of servo mechanism to a position of balance. On the other hand, when the stem H2 moves to the left with respect to the shaft |00, the groove H6 registers f fully with the aperture H and permits full fiow therethrough, whereas the groove no longer registers with aperture |09 reducing the flow and thereby reducing the pressure differential. The piston |04 then moves to the left to a position of balance. In actual practice the servo system responds at once to any movement of the stem H2 and the relative movement of the stem H2 with respect to the shaft |00 will ordinarily neve'r exceed a few thousandths of an inch.

The pressure responsive assembly |02 which controls the position of shaft H2 comprises an aneroid bellows |32 completely enclosed in a cylindrical housing |33 which forms a part of the housing of the injector pump. Ports |34 and |35 are formed in the housing |33 and are spaced so that manifold air may not only be applied to the bellows |32 but will be circulated around the bellows, thus maintaining a uniform temperature throughout the interior of the housing |33. Y

The bellows |32 is filled with dry air and sealed under standard conditions. When th-e engine with which this injector is operated is under full throttle, and operating at sea level, the manifold pressure will be a maximum and then the bellows |32 is compressed, thus moving the bellows stem H2 to the left the maximum distance. Since the servo mechanism responds practically instantaneously to any motion ofthe stem H2 and there is substantially no relative motion therebetween, the piston |04 may be considered as moving to the left with therstem H2 and to the same extent. Movement of the piston |04 to the left causes the piston shaftv |00.to move to the left, thereby pivoting the; cam 83 upwardly and permitting stroke control plunger to move to its uppermost position. With the stop plunger 15 in its uppermost position, injector plunger 31 is permitted its maximum stroke.

As the air throttle of the engine is closed, the manifold pressure drops and consequently the pressure surrounding bellows |32 also drops permitting the bellows to expand and the bellows stem H2 to move to the right. The above described substantially instantaneous follow action of the servo mechanism |03 causes the cam 83 to be pivoted about the stub shaft 84 in a clockwise direction, thereby lowering the stop plunger 15 and thus shortening the stroke of injection plunger 31. It will be evident that by correctly designing the cam surface of the cam 83, any desired proportionate response to change in manifold pressure in the length of the injection plunger stroke may be readily obtained.

It is essential to the operation of the stroke control mechanism that there be no leakage from the high pressure chamber H4 into the aneroid is retained in recess |62 by a helically coiled` spring |63, the left end of which bears against the packing and the right end of which bears against the left, inner side of the piston |04. To prevent leakage of high pressure from between the stem H2 and the shaft |00, a sealing ring |51 is disposed between the left end of shaft |00 and stem H2, the ring |51 being disposed in a recess |64 formed in the left end of shaft |00, and retained therein by washer |58 carried by shaft |00. With this'construction, an effective seal is had with minimum drag between stem H2 and shaft |00. To further avoid any possibility of leakage, the pressure between stem H2 and shaft |00 is reduced by providing a pressure bleed hole |55 in the piston shaft |00 immediately to the right of groove |0I, as viewed in Fig. 3. Hole |55 registers with a wide, annular groove |56 formed `in the periphery of stem H2 and permits pressure to escape from between the stem H2 and shaft |00 into a chamber |60 defined by the interior of the U-shaped cam positioning block 86 and housing 81. Chamber |60 is vented through a peripheral groove |59 formed in the stop plunger supporting block 16 and extending to the annular chamber |25, which latter chamber connects through pressure regulating valve |21 to inlet chamber 32 of the gear pump. In this manner, the pressure in the charnber |60 is reduced to a level corresponding to that of the piston chamber H9. Packing |65 is provided about the periphery of the left portion of shaft |00 to prevent lleakage from the low pressure chamber |60 into the aneroid bellows chamber and is retained in recess |66 by gland nut |61 suitably threaded into the left wall, as viewed in Fig. 3, of the housing 81.

Because of the considerable forces involved, it has been found desirable to reduce insofar as feasible the friction between the cam 83 and the upper end of the stop plunger 15. Thus, in

accordance with a preferred embodiment of this invention the upper 'end of the stop plunger 15 is enlarged and deeply recessed to provide a'support for a ball |36. The ball |36 is freely rotatable within the recess in the upper end of the plunger 15 and the cam 83 rides on the upper surface of the ball. This permits adjustment of the position of the stop plunger 15 with a minimumof friction.

Since the fuel injector pump is driven from the engine, as hereinbefore described, it is supplied with speed sense, and because of the injector plunger stroke regulation in accordance with variations in manifold pressure, the fuel injector pump of this invention also has manifold air density sense and meters the fuel to the engine in response to both speed and load. However, as the airplane or vehicle goes into higher altitudes than sea level, the air pressure surrounding the engine drops, thereby lowering theY exhaust manifold back pressure. With a given manifold pressure, the engine will consume more air under altitude conditions than at sea level and therefore would require more fuel than would be indicated by the manifold bellows |32. A correction must thus be made for this and in order to provide this correction in accordance with this invention, the pressure sensitive capsule |38 is supplied.

secuser Referring to Fig. 3, the pressure sensitiveicapsule |38 will be seen to comprise; a short bellows positioned within the housing |33, at the left end thereof, and attached at its right side by a rivet |39 to the aneroid bellows |32. The left side of bellows |38 is fixed to an externally threaded sleeve |4|, threaded in the left end wall of housing |33l Sleeve |4| vents the capsule bellows |38' to atmospheric pressure, which is permitted to enter bellows |38 through a suitably perforated and screened, small, domed housing |42 mounted on the left end wall of the housing |33 and enclosing the left end sleeve |'4|. Adjustment of the position of the bellows |38 is made by looseningl lock nut |43 and rotating the threaded sleeve |4| to obtain the desired position.

At sea level the bellows |38 will' be more extended with a given manifold pressure in the housing |33 than under higher altitude conditions. Consequently, the bellows |38 will urge the bellows |32 to the right, thereby tending to pivot the cam 813 downwardly and to reduce the stroke of injection plunger 31. Conversely, the relative contraction of the bellows |38 under altitude conditions permits the bellows stem ||2 to move to the left, which movement lengthens the injection plunger stroke for any given manifold pressure above the stroke length which would obtain at sea level for the same manifold pressure.

In accordance with this invention, there is also provided an idle cut-off. This is an important safety feature permitting the engine to be stopped with dry cylinders rather than wet cylinders as would be the case if the engine were shut off by simply switching ofi the ignition. A hot engine stopped with wet cylinders will often accidentally start if the engine is inadvertently turned over.

Referring to Fig. 2, it will be seen that the lower end of the channel 35 by which fluid pressure is normally supplied to the piston 36 and which connects to the channel 34 also connects to a short channel` |44. This channel extends to an idle control valve indicated generally at and positioned in the lower part of the housing Il, as shown in Figs. 2, 4 and '1. The valve |45 comprises a cylindrical chamber |46 in which is rotatably journaled a relatively short valve sleeve |41- The left end of the sleeve |41 is closed, as

viewed in Fig. 7, and a shaft |46 extends therefrom to a crank member` |149 keyed theretowhereby the valve sleeve |41 may be rotated in the chamber |46. A helically coiled spring |5| is positioned within the right portionof the chambei'. |46 and the left end ofthe spring |5| bears against a suitably shouldered portion of the valve sleeve |41, the right end of the spring |5| bearing against chamber cap |52 threaded into the end of the chamber |46. As may be seen in Fig. 7, the valve sleeve |41 does not occupy the full length of the cylindrical chamber |46 in which it is located so that the right portion of the chamber |46 is open. Consequently, there' is a constant supply of pressure from the channel 35 through the connecting channel |44 to the interior of the idle control valve |45. Cross apertures 53 are formed adjacent the left end of the valve sleeve |41 and are arranged to register with vertically extend-ing channel 3| when the sleeve is suitably rotated by the crank |49. The channel |3| is connected to the inlet chamber 32 of the gear pump. Thus, by rotating the valve |41 in the chamber |46, the pressure supplied to the channel 35` may be varied or completely eliminated. With the idle cut-off valve sleeve rotated 90 from the positionshownin Figs. 1, 4 and '1;

fuelunder pressure froml the fuel! supplypump" |0 is led back to the inlet sideof the fuel' supply pump. With this by-pass or bleeding' of fuel from channel 35; there is no pressure to operate the plunger 31 and consequently the fuel injector pump will not supply any fuel to the engine.`

Where herein the various parts of the fuel pump housing, a supply pump in said housing comprising a pair of intermeshing gears, a supporting shaft associated with each gear and journalled in said housing, coupling means on one of said shafts for connecting said shaft in driven relation with a power source, means defining a fuel injector displacement chamber, an axially' reciprocable fuel injector plunger journalled in said chamber, a piston operatively connected with said plungerA for reciprocating the plunger in both directions, valving means for controlling application of pressure to said piston, said valving means being operated by said driven shaft', a fuel distributor chamber and a rotatable valving disc having a plurality of portsY formed therein, passage defining meansv leading from said distributor chamber and adapted to' be sequentially placed in communication with said chamber at selectedl angular positions of said valvi'ng disc, said valving disc being driven by the other of said pumping gear shafts, one of said passage defining means being connected to said fuel inlector plunger displacement chamber and other of said passage dening means being connected to one or more fuel utilization devices.

2. In a fuel injector pump, means' defining a fuel injector displacement chamber, an axially reeiprocable fuel injector plunger journall'ed in said chamber, means for reciprocating said plunger, means for supplying fuel to said chamber, adjustable stop means projecting into said chamber and means for adjusting the amount said stop means projects 'into saldi` chamber, said.

stop means being effective to vary the volumetric,

capacity of said chamber as well as to control the effective length of stroke of said plunger.

3. In a fuel injector pump; means defining. a. fuel injector chamber,- a fuel injector plunger journalied in said chamber, hydraulic means for reciprocating said plunger, a stop plunger hav-. ing a portion thereof disposed in said chamber engageable by said injector plunger for llimiting the length of the injector plunger stroke in accordance with the amount said stopplunger projects into said chamber, said stop plunger controlling the volumetric capacity of said chamber in accordance with the amount said stop plunger projects into said chamber whereby upon a reduc,- tion in injector plunger stroke the volumetric capacity of the chamber is also reduced.

4. In a fuel injector pump inlcombination, a pump housing, a supply pump in said housing comprising a pair of intermeshing gears'a supporting shaft associated with each gear and journalled in said housing, coupling means on one of said shafts for connecting said shaft' in driven relation with a power source', means denin-g a fuel injectordisplacement chamber, an'

axially reciprocable fuel injector plunger' journalled in said chamber, a piston operatively connected with said plunger for reciprocating the plunger in both directions, valving means for controlling application of pressure to said piston, said valving means being operated by said driven shaft, a fuel distributor mechanism in said housing including a fuel distributor chamber and a rotatable valving disc having a plurality of ports formed therein, passage defining means leading from said distributor chamber and adapted to be sequentially placed in communication With said chamber at selected angular positions of said valving disc, said valving disc being driven by the other of said pumping gear shafts, one of said passage defining means being connected to said fuel injector plunger displacement chamber and other of said passage defining means being connected to one or more fuel utilization devices, and a stop plunger having a tip portion thereof projecting into said chamber and engageable With an end of said injector plunger to limit the length f the injector plunger stroke, the volumetric capacity of said fuel injector displacement chamber being varied directly as a function of the length of the injector plunger stroke by said stop plunger.

5. In afuel injector pump, a fuel displacement chamber, a fuel injector plunger movable in said chamber, means for moving said plunger in said chamber, and means operable independently of said plunger and effective to vary the volumetric capacity of said chamber, said means being also engageable with the plunger at one end of the plunger movement to serve as a limit stop for said plunger to regulate the effective length of plunger stroke in accordance with the volumetric capacity of the chamber.

6. In a fuel injector pump, a fuel displacement chamber, a fuel injector plunger movable in said chamber, means for moving said plunger in said chamber, and means operable independently of said plunger operating means for varying the volumetric capacity of said chamber, said means being also engageable with the plunger at one end of the plunger movement to serve asa limit stop for said plunger tov regulate the effective length of plunger stroke in accordance with the volumetric capacity of the chamber.

7. In a fuel injector pump, means defining a fuel injector displacement chamber, an axially reciprocable fuel injector plunger journalled in said chamber, means for reciprocating said plunger, means for supplying fuel to said chamber, an adjustable stop means projecting into said chamber, and means for adjusting the amounts said stop means projects into said chamber effective to bear the volumetric capacity of said chamber as well as to control the effective length of stroke of said plunger, said last means including a servo mechanism responsive to pressure from said fuel supplying means.

8. In a fuel injector pump, means defining a fuel injector chamber, a fuel injector plunger journalled in said chamber, means for recprocating said plunger, a stop plunger having a portion thereof disposed in said chamber engageable by said injector plunger for limiting the length of plunger stroke in accordance with the amount said stop plunger projects into said chamber, said stop plunger controlling the volumetric capacity of said chamber in accordance with the amount said stop plunger projects into said chamber, whereby upon the reduction in injector plunger stroke, the volumetric capacity of the chamber is 16 also reduced, means for supplying fuel tosaid fuel injector chamber, means for varying the position of said stop plunger, said last-mentioned means being responsive to pressure supplied by said fuel supplying means.

9. In a fuel injector pump, means defining a fuel injector plunger chamber, an axially reciprocable fuel injector plunger journalled in said chamber, pressure responsive means for reciproeating said plunger, means for supplying fuel under pressure to said pressure responsive means to reciprocate said plunger, means operable independently of said plunger effective to vary the volumetric capacity of said chamber, and means including a servo mechanism operatively connected with said last-mentioned'means for providing the force required to position said lastmentioned means, said pressure supplying means also supplying fuel to said chamber and supplying pressure to operate said servo mechanism.

10. In a fuel injector pump, means dening a fuel injector displacement chamber, an axially reciprocable fuel injector plunger journalled in said chamber, pressure responsive means for reciprocating said plunger, means for supplying fuel under pressure to said pressure responsive means to reciprocate said plunger, means operable independently of said plunger eective to vary the volumetric capacity of said chamber, said means being also engageable with the plunger at one end of the plunger movement to serve as a limit stop for said plunger to regulate the effective length of -plunger stroke in accordance with volumetricl capacity of the chamber, and means including a manifold and atmospheric pressure responsive servo mechanism operatively connected with said volumetric capacity varying means for providing the force required to position said volumetric capacity varying means, said pressure supplyingK means being also connected to said chamber and said servo mechanism for supplying fuel to said chamber and for supplying pressure to operate said servo mechanism.

11. In a fuel injector pump in combination, a pump housing, a supply pump in said housing comprising a pair of intermeshing gears, a supporting shaft operatively connected with each gear and journalled in said housing, coupling means on one of said shafts for connecting` said shaft in driven relation Wiith a power source, means defining a fuel injection displacement chamber, an axially reciprocable fuel injector plunger journalled in said chamber, a piston 0peratively connected with said plunger for reciprocating the plunger in both directions, valving means for controlling the application of pressure to said piston, said valving means being operated by said driven shaft, a fuel distributor pump and a rotatable valving disc having a plurality of ports formed therein, passage defining means leading from said distributor chamber and adapted to be sequentially placed in connection with said chamber at selected angular positions of said valving disc, said valving disc being driven by the other of said gear shafts, one of said passage defining means being connected to the fuel injector plunger displacement chamber, another of said passage defining means being connected to one or more fuel utilization devices, means for varying to volumetric capacity of said fuel injector displacement chamber, said means including an atmospheric and manifold pressure responsive means and a servo mechanism operatively connected with said last-mentioned means for providing the force necessary to position the means for varying the volumetric capacity of said fuel injector displacement chamber, another of said passage defining means connecting said supply pump to said servo mechanism, said servo mechanism and means for reciprocating the fuel injector plunger being responsive to the pressure supplied by said supply pump.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 217,626 Lyman July 15, 1879 657,160 Eads Sept. 4, 1900 830,099 Packard Sept. 4, 1906 851,262 Tatum Apr. 23, 1907 Number 18 Name Date Higgins, Jr Apr. 26, 1921 Johanson May 10, 1921 Scott July 28, 1931 Wallace Feb. 20, 1934 Douglas July 30, 1935 Junkers Sept. 3, 1935 Koster et a1 Mar. l0, 1936 Vincent Sept. 8, 1936 Udale Feb. 17, 1942 Price Ajpr. 21, 1942 Tucker et al. Dec. 7, 1943 Summers Jan. 21, 1947 Wallace Apr. 13, 1948 Hanna Oct. 18, 1949 Monoyer Apr. 15, 1952 

